Interstate 39

I-39 in Illinois goes from the Wisconsin line south to Bloomington/Normal down the center of Illinois. Except for the sections around Rockford, I-39 carries comparitively little traffic for an interstate highway. I-39 serves as a convenient route to take traffic from the upper midwest to the southeast or southwest, and serves as a distance bypass to Chicago for some travellers. In Illinois, I-39 was completed in the 1980s, but the part on the Northwest Tollway was not signed as I-39 until around 2003.

I-39 begins in Wausau, Wisconsin and ends in Normal, Illinois at I-55.